Surgical anatomy

The appendix is a narrow blind-ended tube that is attached to the posteromedial end of the cecum.

Common positions of the appendix

The position of appendix is highly variable and can be categorised into seven main locations depending on its relationship to the ileum, caecum or pelvis. The most common position is retrocecal (65.28%). They may also be remembered by their relationship to a clock face:

• Pre-ileal located anterior to the terminal ileum (1 or 2 o’clock).
• Post-ileal located posterior to the terminal ileum (1 or 2 o’clock).
• Sub-ileal located parallel with the terminal ileum (3 o’clock).
• Pelvic descending over the pelvic brim (5 o’clock).
• Subcecal located below the cecum (6 o’clock).
• Paracecal located alongside the lateral border of the cecum (10 o’clock).
• Retrocecal located behind the cecum (11 o’clock)

Neurovascular supply of the appendix

Arterial supply is from appendicular artery and venous drainage is via the corresponding appendicular vein.

The appendix is innervated by sympathetic and parasympathetic branches of the autonomic nervous system achieved by the ileocolic branch of the superior mesenteric plexus.